So what do I mean by theoretical performance? Well, Nim is a statically typed and compiled language, it stands to reason that these attributes make it very performant indeed. Even if certain aspects of the language are not efficient right now, you can bet that it will be fairly trivial to improve their performance. For languages like Python, Ruby, etc. you are heavily limited by the dynamic typing (which restricts the amount of information you have about the code) and the fact that they are primarily interpreted languages. You will need to put far more effort into optimising them than compiled languages.
As a side note, I do intend to improve the performance of Jester as well. But I'm not the only one doing this, the mofuw framework is #24 on the TechEmpower benchmarks right now.[1]
If the speed of an HTTP framework impacts your application you have an architecture problem.
Nim CPU, memory and compile time performance are excellent in most benchmark.
From what I’ve seen for Jester/Nim, it’s not really benchmarked a lot, and it doesn’t seem particularly fast where it is benchmarked. This could perhaps be fixed by better implementations for the benchmarks or some optimization in Jester itself.
I think a strong story for performance would go a long way towards improving awareness of Nim. Crystal does very well in such tests, and I think that is one of the most appealing parts of the language. In fact, I evaluated both Nim and Crystal for server side development a while back, and quickly dismissed Nim because it didn’t seem to be all that fast. I eventually dismissed Crystal too because of the compile times and syntax, but I put a lot more time into it.